CBOT brokers reported that funds bought 12,000 contracts of corn, 5,500 contracts of soybeans, and 4,800 contracts of wheat.
The most active corn contract for July delivery rose 5.75 cents, or 1.47 percent to settle at 3.9575 dollars per bushel. July wheat delivery went up 14.75 cents, or 3.05 percent to close at 4.99 dollars per bushel. July soybeans were up 5.25 cents, or 0.51 percent to settle at 10.3925 dollars per bushel.
CBOT wheat continued its rally in the second straight day with sharp gains, on short- covering after prices fell to the lowest level in a week.
The CBOT traders are also paying attention to conditions of key overseas wheat producers. The eastern Australian drought is deepening with the forecast for another two weeks of hot and dry weather.
Soybeans got some support from President Donald Trump's confirmation on Tuesday that he would send a high-ranking team to China to start negotiations on trade dispute with China.
Additional support to soybeans came from reported shipping delay out of Argentina, which might turn some of demand for soybean meal or soybeans to the U.S..